The present invention relates generally to the field of nanoscale sensors, and more particularly to an apparatus and method for detecting a target species using nanoscale sensors.
Chemical and biological sensors typically operate at elevated temperatures to enhance chemical reactivity, and often require long recovery times (if recoverable at all), poor reproducibility, and are applicable to the detection of a very limited range of chemical and biological species and are described in U.S. Pat. No. 7,013,708, entitled “Carbon Nanotube Sensors”; U.S. Pat. No. 7,166,325, entitled “Carbon Nanotube Devices”; U.S. Application Publication No. 2003/0134267, entitled “Sensor for Detecting Biomolecule Using Carbon Nanotubes”; U.S. Application Publication No. 2004/0245209, entitled “Method for Fabricating a Carbon Nanotube Array and a Biochip Using the Self-Assembly of Supramolecules and Staining of Metal Compound”; U.S. Application Publication No. 2005/0181409, entitled “Biochip and Biomolecular Detection System Using the Same”; and U.S. Patent Application Publication No. 2005/0230270, entitled “Carbon Nanotube Nanoelectrode Arrays.”
An article by Choi et al., entitled “YY1-DNA interaction results in a significant change of electronic context as measured by capacitance,” Biophysical Chemistry 103, 109-115 (2003), which is incorporated herein by reference in its entirety, describes a nanosensor that detects a dielectric change upon the formation of a specific Yin-Yang 1 (YY1)-DNA complex within an 80-nm gap between two electrodes of a capacitor. Aliquots of a mixture of YY1 and P5 promoter DNA were placed on the capacitor and, after a 5-min incubation period, the capacitance was measured between 10 kHz and 3 MHz. Changes in the capacitance were attributed to the specific YY1-DNA complexation. It is believed that the dielectric effect is due to the alignment of dipoles to the electric field of the capacitor, whereby a stronger dipole results in greater capacitance. However, the sensitivity of the device suffered due to signal contributions arising from complexation and other contributions outside of the electrode gap.